Laser beam converging device
Through the coordination of the zoom lens group and the stepper motor, the efficient convergence of the laser beam in complex environments is achieved, which solves the problems of low efficiency and low accuracy in laser processing, and improves the degree of automation and beam quality of laser processing.
Patent Information
- Application Number
- CN202422598227.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2034-10-28
AI Technical Summary
In existing laser processing, fixed lathes have low processing efficiency, low accuracy, and are susceptible to mechanical vibration, resulting in poor cutting consistency. Common zoom lenses have complex structures and high environmental requirements, and serious laser power loss.
The zoom lens group, stepper motor and movement mechanism are adopted to control the movement of the stepper motor through the controller to achieve accurate movement of the zoom lens group. The double-glued lens is used to eliminate spherical aberrations and ensure that the laser beam gathers efficiently in complex environments.
It improves the detection efficiency and automation of laser processing, ensures beam quality and imaging quality, avoids the out-of-focus problem of multi-lens structures, adapts to complex environments, and improves the utilization rate of laser energy.
Smart Images
Figure CN223217720U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of laser energy measurement, in particular to a laser beam converging device. Background Art
[0002] With the development and popularization of laser technology, laser technology has been widely used in mechanical processing, laser cutting, laser rust removal, and laser marking due to its excellent characteristics. The accuracy of laser processing depends not only on the power density of the laser beam, but also on the ability of the converging lens to focus the laser beam.
[0003] Laser processing involves focusing the energy emitted by a laser onto a small target area and transferring heat to the material being processed. The laser processing process is highly dependent on the energy absorption capacity of the material. Process efficiency is often a function of the square or cube of the irradiance. Therefore, the total energy and spatial distribution of the focal spot on the workpiece are critical to the success of the process and are highly sensitive to deformations in the spatial energy distribution of the laser beam. In laser welding, the gap between parts must be precisely controlled, requiring the laser beam energy to be consistently directed to the same target area without focal drift. If high-speed welding is performed, poor beam structure can lead to poor welds. In laser cutting, beam quality and focusing ability are crucial to the quality of the cut itself. Poor beam quality can result in scrapped parts or rework, increasing costs. Therefore, obtaining a high-quality laser beam is a core issue in laser processing.
[0004] The production process of laser processing often exists in a complex environment. In the process of large-scale industrial production, fixed lathes are used for processing with fixed-focus lenses, which often require manual continuous mechanical adjustment. This is often inefficient and has low precision. Long working hours are prone to mechanical vibration problems, and cutting consistency is not strong.
[0005] A typical zoom lens typically consists of a front fixed lens group, a zoom lens group, a compensating lens group, and a rear fixed lens group. These complex structures often include several or even dozens of lenses, requiring high operating conditions. Excessive mechanical vibration can easily cause defocusing. The large number of lenses also results in significant loss of laser power, leading to their seldom use in laser processing. Utility Model Content
[0006] In response to the shortcomings of the existing technology, the utility model provides a laser beam convergence device, including a zoom lens group, a stepper motor, a moving mechanism and a controller, wherein the zoom lens group is used to converge the incident laser onto a working interface; the stepper motor is used to receive commands from the controller and drive the moving mechanism to a specified position; the moving mechanism is used to load the zoom lens group and move under the drive of the stepper motor to achieve zooming; the controller is used to send commands to the stepper motor to control the movement of the stepper motor.
[0007] Furthermore, the zoom lens group includes a fixed lens, a variable magnification lens and a compensating lens.
[0008] Furthermore, the fixed lens, the zoom lens and the compensating lens are all doublet lenses.
[0009] Furthermore, the fixed lens includes a first curved surface, a second curved surface, and a third curved surface, and the curvature radii of the three curved surfaces are all positive values.
[0010] Furthermore, the zoom lens includes a fourth curved surface, a fifth curved surface, and a sixth curved surface, and the curvature radii of the three curved surfaces are all positive values.
[0011] Furthermore, an aperture is provided between the fixed lens 1 and the zoom lens 2 to control the laser beam into a circular shape and ensure the distribution of laser energy on the laser working interface.
[0012] Furthermore, the compensation lens 3 includes a seventh curved surface, an eighth curved surface and a ninth curved surface. The curvature radius of the seventh curved surface is positive, the curvature radius of the eighth curved surface is negative, and the curvature radius of the ninth curved surface is negative. The overall effect of the three curved surfaces is to converge the laser beam.
[0013] Furthermore, the displacement accuracy of the stepper motor is no more than 0.1 mm.
[0014] Furthermore, the moving structure includes a guide rail and two sliders, on which a zoom lens and a compensation lens are mounted respectively. The sliders are connected to a stepper motor and move under the control of the stepper motor, thereby driving the movement of the lens.
[0015] Furthermore, it also includes a shell, which is provided with a conical, hollow spout at the image end, with air holes opened on the side of the spout, and filters placed at both ends of the spout.
[0016] Compared with the prior art, the laser beam converging device provided by the present invention has the following beneficial effects:
[0017] (1) Using a zoom lens group, the working distance of mechanical processing can be changed by adjusting the focal length to adapt to complex working environments, which can greatly improve detection efficiency and increase the degree of production automation.
[0018] (2) The lenses in this design all use double-cemented lenses, which can eliminate the spherical aberration of the lens, thereby improving the beam quality and imaging quality of the optical system.
[0019] (3) According to the characteristics of laser, three double-cemented lenses are used to achieve optical zoom, which simplifies the structure and effectively avoids the problem of multiple lenses being easily out of focus. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a schematic diagram of the overall structure of a laser beam converging device according to an embodiment of the present invention;
[0021] Figure 2 This is a schematic structural diagram of a zoom lens assembly according to an embodiment of the present invention;
[0022] Figure 3 This is a schematic structural diagram of a moving mechanism according to an embodiment of the present invention;
[0023] Figure 4 It is a structural schematic diagram of a spout of an embodiment of the present utility model. DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0025] The utility model provides a laser beam converging device, such as Figure 1 As shown, it includes a zoom lens group, a stepper motor, a moving mechanism and a controller 8, wherein the zoom lens group is used to converge the incident laser to the working interface; the stepper motor is used to receive the controller command and drive the moving mechanism to the specified position; the moving mechanism is used to load the zoom lens group and move under the drive of the first stepper motor 10 and the second stepper motor 15 to achieve zooming; the controller 8 is used to send commands to the stepper motor to control the movement of the stepper motor.
[0026] The zoom lens group includes a fixed lens 1, a variable magnification lens 2 and a compensating lens 3. Figure 2 As shown, the optical axis of the visible light beam is coupled to the optical axis of the laser beam, so that the working plane of the laser beam and the imaging plane of the visible light beam are on the same optical axis.
[0027] In this utility model, it is assumed that the incident light can propagate from left to right. The area to the left of the optical lens is the object side, or object space, and the area to the right of the optical lens is the image side, or image space. Since the incident light propagates from left to right, based on the intersection of the spherical surface (i.e., curved surface) and the principal optical axis, the radius of curvature is negative if the center of the sphere is to the left of the intersection; conversely, the radius of curvature is positive if the center of the sphere is to the right of the intersection. It is understood that the sign of the radius of curvature only indicates the direction of the surface's curvature, while the magnitude of the number indicates the degree of curvature.
[0028] In one embodiment, the fixed lens 1 , the zoom lens 2 and the compensating lens 3 are all doublet lenses, and the three lenses can be made of different materials, such as flint glass or crown glass.
[0029] In one embodiment, the fixed lens 1, the zoom lens 2 and the compensation lens 3 are converging lenses. After gradual convergence, when the laser beam passes through the last lens and converges to the working interface, the change in beam diameter will be relatively small when the focal length of the laser beam changes.
[0030] The fixed lens 1 includes a first curved surface, a second curved surface and a third curved surface. The first curved surface faces the object side and is concave toward the image side, the second curved surface faces the object side and is concave toward the image side, and the third curved surface faces the object side and is concave toward the image side. The curvature radii of these three curved surfaces are all positive values to initially converge the laser.
[0031] The zoom lens 2 includes a fourth curved surface, a fifth curved surface and a sixth curved surface. The fourth curved surface faces the object side and is concave toward the image side, the fifth curved surface faces the object side and is concave toward the image side, and the sixth curved surface faces the object side and is concave toward the image side. The curvature radii of these three curved surfaces are all positive to further converge the laser.
[0032] An aperture is placed between the fixed lens 1 and the zoom lens 2 to control the laser beam into a circular shape, ensuring the distribution of laser energy on the laser working interface. At the same time, when the laser passes through the field aperture, it eliminates interference from other frequencies due to the different refractive indices.
[0033] Compensating lens 3 includes a seventh curved surface, an eighth curved surface, and a ninth curved surface. The seventh curved surface faces the object side and is concave toward the image side. The eighth curved surface faces the image side and is concave toward the object side. The ninth curved surface faces the image side and is concave toward the object side. The curvature radii of these three surfaces are positive for the seventh curved surface, negative for the eighth curved surface, and negative for the ninth curved surface. However, the overall effect is to converge the laser beam, ultimately converging it onto the working interface.
[0034] The function of the zoom lens 2 is to achieve the purpose of zooming through its own linear movement. At the same time, the focal length of the zoom group and the focal lengths of other groups jointly affect the total focal length of the system.
[0035] The compensating lens 3 compensates for image plane displacement caused by the linear motion of the zoom lens during zooming. The positions of the zoom lens and the compensating lens are in a one-to-one correspondence. For different positions of the zoom lens and the compensating lens, they must be moved to specific positions to maintain a stable image plane position. In this design, the first stepper motor 10 and the second stepper motor 15 have a displacement accuracy of no more than 0.1 mm, respectively controlling the movement of the zoom lens and the compensating lens.
[0036] In one embodiment, the curvature radii (R1-R9) of the first to ninth curved surfaces have an allowable tolerance of less than 5%, and upper and lower deviations are less than 2%.
[0037] In one embodiment, the controller 8 can calculate the positions of the zoom lens 2 and the compensation lens 3 based on the spot size of the working interface, and then send commands to the first stepper motor 10 and the second stepper motor 15 to control the stepper motor to drive the moving mechanism, thereby driving the zoom lens 2 and the compensation lens 3 to move, ultimately achieving the purpose of adjusting the focal length and allowing the laser energy to better converge on the working interface.
[0038] The zoom lens 2 and compensating lens 3 are mounted on a movable mechanism. This movable mechanism can be constructed using existing technology, such as a guide rail and a slider. The guide rail is fixed to the ground or a tabletop, and the zoom lens or compensating lens is mounted on the slider. The slider is connected to a stepper motor and is controlled by the stepper motor to move, thereby driving the movement of the lens.
[0039] In one embodiment, a housing 16 is further included, and guide rails and sliders 12 and 13 are provided at the bottom of the housing 16. Figure 3 As shown, a zoom lens 2 is provided on the slider 12 and is connected to a first stepper motor 10, and a compensating lens 3 is provided on the slider 13 and is connected to a second stepper motor 15, so that the zoom lens and the compensating lens move in the housing through the movement of the stepper motor.
[0040] In one embodiment, the shell is also provided with a spout at the end close to the working interface to protect the converged light from being disturbed in the distance from the compensation lens to the working interface (the shell also has a corresponding function). At the same time, the spout is also affected by the sputtering of the processing material during the laser processing. Figure 4 As shown, the spout is a conical, hollow structure with air holes 6 on the side. After placing the filters at both ends of the spout, air is inflated through the air holes 6. The air pressure inside the spout tightly fits the two filters to the two ends of the spout to form a closed structure. When replacing a new filter, it only needs to flush with protective gas and apply negative pressure to complete the replacement, which improves the utilization rate of the product. After the laser comes out of the compensation lens group, it passes through the filter and enters the air chamber. The gas in the air chamber protects the laser beam, and the filter is used to isolate the reflected light to protect the laser and prevent sputtering during the laser processing process.
[0041] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A laser beam converging device, characterized in that: The system includes a zoom lens group, a stepper motor, a moving mechanism, and a controller. The zoom lens group is used to focus the incident laser light onto the working interface. The stepper motor is used to receive commands from the controller and drive the moving mechanism to a specified position. The moving mechanism is used to carry the zoom lens group and move under the drive of the stepper motor to achieve zooming. The controller is used to send commands to the stepper motor to control the movement of the stepper motor. The zoom lens group includes fixed lens, variable magnification lens and compensating lens; Fixed lens, zoom lens and compensating lens are all doublet lenses; The moving structure includes a guide rail and two sliders. The zoom lens and the compensation lens are installed on the sliders respectively. The sliders are connected to the stepper motor and move under the control of the stepper motor, thereby driving the movement of the lens. The invention also comprises a shell, which is provided with a conical, hollow spout at the image end, with air holes opened on the side of the spout, and filters placed at both ends of the spout.
2. The laser beam converging device according to claim 1, characterized in that: The fixed lens includes a first curved surface, a second curved surface and a third curved surface, and the curvature radii of the three curved surfaces are all positive values.
3. The laser beam converging device according to claim 1, characterized in that: The zoom lens includes a fourth curved surface, a fifth curved surface, and a sixth curved surface, and the curvature radii of the three curved surfaces are all positive values.
4. The laser beam converging device according to claim 1, wherein: An aperture is provided between the fixed lens and the zoom lens to control the laser beam into a circular shape and ensure the distribution of laser energy on the laser working interface.
5. The laser beam converging device according to claim 1, wherein: The compensation lens includes a seventh curved surface, an eighth curved surface and a ninth curved surface. The curvature radius of the seventh curved surface is positive, the curvature radius of the eighth curved surface is negative, and the curvature radius of the ninth curved surface is negative. The total effect of the three curved surfaces is to converge the laser beam.
6. The laser beam converging device according to claim 1, characterized in that: The displacement accuracy of the stepper motor is no more than 0.1mm.